Abstract
Nutrient arteries of the bilateral coracobrachialis muscles in 10 Japanese adult cadavers were examined and the study is summarized herein. The coracobrachialis muscles were divided into four classifications in accordance with the origin and pattern of distribution of the supplying arteries. The coracoid process artery (Sato・Takafuji 1985) supplied the Type 1 muscle but was absent in Type 2. The profunda brachii artery supplied the Type a muscle but was absent in Type b. The Type 2-a coracobrachialis muscle was most frequently observed, being found in seven cases in which the upper portion of the muscle was supplied by the coracobrachialis artery (Sato, 1980), the central portion by the coracobrachialis branch (supplying this muscle alone) arising from the axillary artery and the profunda brachii artery, and the lower portion by the coracobrachialis branch and the common stem of muscular branches (supplying this and other muscles), both originating from the brachial artery. Calculation of the distribution ratios of arteries in the four types of muscle revealed that the coracobrachialis artery existed in all specimens, supplying 38.3 % of the entire muscle. On the basis of this finding, the coracobrachialis artery was considered the main artery of the coracobrachialis muscle. In two specimens demonstrating the superficial brachial artery, the coracobrachialis artery arose from the deep brachial artery and supplied both the coracobrachialis and biceps brachii muscles. The total numbers of arteries ranged from 4 to 7, with five (in 11 cases) being most common.
